Rootstock Smart Bitcoin (RBTC) is a cryptocurrency tied 1:1 with Bitcoin, enabling smart contract execution on the Rootstock sidechain. It is used for transaction fees within the RSK network, leveraging Bitcoin’s security while enhancing functionality with faster confirmations and smart contract support. RBTC was created by RSK Labs, co-founded by Adrian Eidelman, and launched in 2018, benefiting from merged mining with Bitcoin.